Showing posts with label F-4E PHANTOM II. Show all posts
Showing posts with label F-4E PHANTOM II. Show all posts

The F-4E Phantom II: Simulating the 'Analog Storm' in X-Plane 12

[VSKYLABS Dev-Notes] issued 15th February 2026

Project development will soon be fully channeled to completing the F-4E cockpits (forward, aft), and to the completion of deep systems integration, including advanced featured and fail-modes throughout the F-4E operational envelope.

Here is a 'taste' of what's coming up in the development:

Both cockpits are being developed to be fully-functional in the initial release version. When engineering a high-fidelity F-4E simulation in X-Plane, which is above all a cutting edge aerodynamics and physics based flight simulator, 'Flying' the F-4E is 100% of the experience. We have no enemy engagement, no systems/warfare tactics. X-Plane provides a pure 'Test-Pilot' environment, in my perspective.

One of the most fascinating aspects of the above, is that it provides a rare opportunity to experience some of the real-world challenges of the F-4 Phantom II aircraft: flying the aircraft in the flight instructor seat, that is - operating and flying the aircraft from the back-seat. Forward visibility from the back-seat is one of the worst. Coupled with a sluggish, AoA sensitive aircraft - takeoff and landing from the back-seat becomes a true challenge, especially in heavy configurations. The VSKYLABS 'Test-Pilot' F-4E is being developed to provide full back-seat operations which will be deeply evaluated in full VR operations to provide the closest experience compared to the real-thing.

VSKYLABS F-4E Phantom II WIP showing the aircraft in X-Plane 12 environment

Another major development focus is channeled to 'aircraft (un)forgiveness' in the various phases of flight and operation modes. The F-4 Phantom II is not a forgiving aircraft. It is one of the last iconic, heavy, jet-fighter aircraft still flying, which has a 50's era aero-design and direct control interface to the pilot hands and feet. It has a very 'old' stability augmentation system, which is incomparable to the modern/late fly-by-wire aircraft. 

The VSKYLABS F-4E will have this Raw, 'Analog storm' embedded within, thanks to the advanced physics and delta-wing simulation capabilities of X-Plane 12.

In addition to aircraft performance, control handling characteristics and overall systems integration, the VSKYLABS F-4E will include a wide-set of failing modes and self-induced 'emergencies'.

Here are some examples of the simulated modes, to get into perspective:

  • Replicating the authentic J79-GE-17 operating envelopes. Exceeding these and expect afterburner light-off, compressor stalls or flame-outs.
  • Engines flame-out during abort takeoff in cold weather: In the F-4E, when operated from runways which are covered with excessive water, snow or slush, high-speed aborts may result in engine flame out, due to precipitation ingestion! The probability of such flame-out is highest when the throttles are chopped from full afterburner to IDLE at speeds above 100 knots. In case of double-flame out, normal braking, anti-skid protection and nose-gear steering will be lost. This behavior is fully simulated.
  • Departures and Spins (including recovery).
  • Authentic F-4E-Specific Zoom Climb - including afterburner blowout and all other relevant characteristics. We don't have active warfare in X-Plane, but we can fight the flight envelope!
  • Authentic Single-Engine Performance and handling qualities. 
  • (intentionally left blank...).
  • And much, much more!

One of the greatest advantages of simulating a high-fidelity simulation of the F-4E in X-Plane 12 is that the 'Test-Pilot' can channel 100% of his attention to the core F-4E systems and to how to FLY it. The fact that we don't have a living warfare in X-Plane becomes an advantage especially for new pilots who wishes to have a close look-and-feel of the F-4E.



In the F-4 Phantom II, high Alpha regime, heavy takeoffs and practically any landing are not trivial and must be executed following deep understanding of the F-4 raw behavior. This is huge. For that reason VSKYLABS develops the F-4E with great attention to 'New Pilot Conversion' of all kinds of pilots in X-Plane. Under the 'Jet-fighter' skin, the F-4 Phantom II is 'Just' a fascinating aircraft that can provide endless hours of interaction and exploration. Not only for 'Jet-Fighter-Lovers'. 

I just completed one of the test flights in the VR environment and oh-boy...I can't wait sharing a few close-up screenshots of the evolving cockpit(s). The development threshold in this aspect has not reached the mature-phase that allows sharing these, but if all goes as expected, first close-up screenshots will be available for sharing within 2-3 weeks.

Stay tuned! 

Huss
VSKYLABS

VSKYLABS F-4E Phantom II WIP pulling up in a test-flight in X-Plane 12
VSKYLABS F-4E Phantom II WIP showing the model in-game X-Plane 12 with the canopies opened and flaps down, standing still.

VSKYLABS - 10 Years in the 'Labs!

[VSKYLABS Newsletter] issued 3rd January 2026

By Huss @ VSKYLABS

Hello everyone,

When I opened the official doors of VSKYLABS back in 2015, I didn’t set out to build a typical flight-simulation add-on 'studio'. The goal was something else entirely: a virtual lab where challenging, unconventional, and historically significant aircraft could be explored properly, pushed, tested, and understood using X-Plane as the ultimate sandbox and physics engine behind it.

As we cross the 10-year mark, I’ve been revisiting old forum threads, project logs, and development notes. What follows are a (very) few lateral insights and behind-the-scenes principles that have quietly shaped the VSKYLABS journey from X-Plane 5 all the way to the cutting edge of X-Plane 12.

*VSKYLABS has been experimenting and developing aircraft in the X-Plane environment since around the year 2000 (X-Plane 5). The year 2015 marks the point where all activities became official.


Covering a decade of X-Plane and real-world aerospace-related activites plus development journeys of around 37 VSKYLABS add-on products is a delicate task. Instead of going into the micro-details, I decided to focus on the core-componentes which shaped the most of the essence of VSKYLABS and its fleet, throughout the years;

VSKYLABS Origins: Experimental Foundations (2000–2014):

In the years leading up to 2015, experimentation focused heavily on lifting bodies, unconventional configurations, and non-standard flight regimes in X-Plane. These early projects were mostly in-house, some were shared as freeware. They meant to probe X-Plane, Plane Maker and their limits: how it handled marginal stability, center-of-gravity sensitivity, Angle-of-Attack, non-classical control authority, transitions between regimes and propulsion systems. All compared to extensive real-world experience or real-world authentic flight reports.

This period laid the conceptual foundation of VSKYLABS. Those activities would later shape everything from taildragger behavior to supersonic flight at the edge of X-Plane's 'space'.

In those early days, the VSKYLABS aircraft were developed almost entirely within Plane-Maker itself, while the first experimental steps toward custom 3D modeling has initiated.

*Various 'Early' VSKYLABS projects. Delta-wing and lifting bodies airframes took the lead in X-Plane's flight model and aircraft engineering exploration.


The Early Years: Becoming VSKYLABS as we know it today (2015–2017):

The VSKYLABS projects were never driven by market demand or popularity. They were driven by what can X-Plane really do, across the entire flight model spectrum.

During this phase, VSKYLABS avoided focusing on a single aircraft category. Fixed-wing aircraft were only part of the picture. RC-Model airplanes, Autogyros and trikes entered the hangar early as essential tools for understanding how X-Plane behaves at the edges of conventional aerodynamics; low inertia, rotor-disk aerodynamics, weight-shifting, thrust-line sensitivity, and unconventional stability regimes.

This approach dictated deep 'crawling' inside Plane-Maker and X-Plane's flight model, covering practically all that X-Plane can deliver as a physics-based flight simulation platform.

The early VSKYLABS trike and autogyro projects ran in parallel with fixed-wing exploration, allowing to stress-test X-Plane across vastly different flight dynamics models. This cross-category approach revealed limitations, strengths, and quirks that would have remained hidden within a single aircraft class.

Understanding X-Plane and how pilot inputs translate into dynamic flight across very different aircraft types in X-Plane laid the groundwork for everything that followed. By the end of this phase, VSKYLABS had established a solid technical foundation, allowing more complex 3D modeling, aircraft depth, and interaction layers to be introduced with confidence in later projects.

*The VSKYLABS Tecnam P2006T, initially released in May 2017.


The 'X-Plane cockroaches' Philosophy:

From day one, I’ve maintained a strict zero third-party plugin approach. VSKYLABS is, and will remain, 100% X-Plane native.

The reason is simple: VSKYLABS aircraft are designed to become part of X-Plane’s DNA. When a new X-Plane beta drops, VSKYLABS aircraft are usually among the first cleared for takeoff. They 'speak' the same language as the core engine. If a native X-Plane aircraft flies, a VSKYLABS aircraft will fly too, as they share the same internal dependencies.

In practical terms: VSKYLABS aircraft are built like 'X-Plane cockroaches'. Resilient by design, and highly likely to survive even major platform updates.

The most visible demonstration of this philosophy was the launch of X-Plane 12, where the entire VSKYLABS fleet was ready on day one of its 'Early Access' release. Another interesting fact is that a huge portion of the leading VSKYLABS aircraft in the present (X-Plane 12.4.x) have been initiated as X-Plane 10 & X-Plane 11 aircraft!

*Evolving through X-Plane eras; Both the VSKYLABS C-47B and the VSKYLABS EuroFOX have been initially released for X-Plane 10.51, went through several major-restoration updates to fall in line with the latest X-Plane 12 standards, features and flight dynamics innovations.


The 'Test-Pilot' Series:

You’ve probably heard the term 'Study-Level'. It’s usually associated with deep systems modeling, and that’s valid. But coming from a background that includes thousands of flight and instruction hours on props, turboprops, and high-performance jets, and from spending a significant part of my life inside real flying cockpits of a large variety of aircraft categories, I chose to evolve the 'Study Level' idea into what I call the VSKYLABS Test-Pilot series.

The focus shifted toward aircraft flight handling in all phases of flight, flight envelope and flight performance engineering.

Over time, this philosophy spread laterally across the VSKYLABS fleet, and today all VSKYLABS aircraft carry the Test-Pilot stamp. This is not related to systems complexity, but because of how they fly.

Take the Rutan Long-EZ as an example. System-wise, it’s a simple homebuilt aircraft. But exploring its full envelope, differential rudder-brakes, stall behavior, cruise efficiency...is pure 'test-pilot' territory, in real-world operations as well.

Now apply that same mindset to the C-47/DC-3, SR-71, LSA & Bushplanes, helicopters like the Hungarocopter HC-02, NISUS Gyroplane, and in practice, the entire VSKYLABS fleet. I find pilot-airframe interaction as the most fascinating aspects of flight, and in my perspective, this is what X-Plane was built for in the first place.

*The VSKYLABS Rutan Long-EZ as a case-sample of Test-Pilot approach in development and flying, both in real-world and in X-Plane. The project is about to have a major update release in the very near future.


Looking Ahead: 2026:

I’m truly excited about where we’re heading.

Supersonic Jets:
The return of the VSKYLABS 'Test-Pilot' 
F-4E Phantom II, the IAI Lavi, and the continuous development of the VSKYLABS XR-71-TB are taking center stage.

Lifting Bodies are BACK!
For those who remember the early days of the VSKYLABS X-24A and M2-F2 “flying bathtubs”, 2026 marks a serious return to high-speed, low-lift research vehicles!

Updates & Maintenance:
With the LSA, GA, and helicopter fleets now stable and fully aligned with X-Plane 12, ongoing quality and maintenance updates continue across the board in 2026.

And yep...there are a few confidential projects quietly progressing in the hangar.

*The WIP VSKYLABS 'Test-Pilot': F-4E Phantom II. Developed based on extensive, real-world F-4E flying experience.


I’ve personally taken part in thousands of discussions on our forums over the past decade. That feedback loop is a major driver behind everything you see today.

Thank you for being part of VSKYLABS for the last 10 years.
Personally, it feels like we’re just getting started!

Wishing you all an amazing 2026,

Huss
VSKYLABS
VSKYLABS Aerospace Simulations


Variable-Area Nozzles in Jet Afterburners

[Test-Pilot Report] issued 23rd August 2021

The F-4E is powered by two J79-GE-17 engines, where each engine is equipped with an afterburner. A fact that may be new to some: Afterburning engines are designed with variable-geometry exhaust nozzles!


Engines with afterburners are equipped with variable area exhaust nozzles. The purpose of the variable area nozzle is to utilize maximum thrust from a given jet-flow, and to accelerate the exhaust-jet velocity from subsonic to supersonic velocity (in afterburner mode), to fully utilize the afterburner system.

The internal geometry of the nozzle in this case must be of a convergent-divergent cross section, as convergent nozzles cannot accelerate the exhaust jet velocity into the supersonic regime (in short - as the flow exceeds the sonic regime in the nozzle, shock waves are formed in the convergent cross-section, reducing the jet velocity to subsonic right after...).

To form a convergent-divergent cross-section that allows supersonic flow, the variable area exhaust nozzle includes TWO sets of cylindrical nozzles, that are working together (per engine).

The inner nozzle controls the convergent section of the nozzle, while the outer nozzle controls the divergent section. The two nozzle sections are linked together, forming the required cross-section during engine operation.

When the engine is set to full "dry" power (without afterburner), the inner nozzle opens while the outer nozzle closes. The whole nozzle is working in this case as a convergent cross-section nozzle.

When the afterburner is ignited, the inner nozzle closes, while the outer nozzle opens widely. Now the nozzle is set with a convergent-divergent cross section (similar to a rocket nozzle).

Jet flow accelerates in the convergent section and proceeds to the divergent section, becoming supersonic. The shock waves may be visible as "rings" as the high energy, high velocity jet leaves the divergent section, behind the aircraft.

The (upcoming) VSKYLABS F-4E Phantom II is equipped with functional variable area exhaust nozzles that works with two, animated nozzle sections for each engine, forming a convergent-divergent cross-section during engine operation from idle to afterburner. To note that when on idle, the nozzles are widely opened, mainly to reduce the thrust to minimum.

The featured screenshot in this post shows the (Work In Progress) variable area nozzles in action, where the right-hand engine is set to maximum "dry" thrust (no afterburner), and the left-hand engine is set to idle.



Stay tuned for more development news of this fascinating project!

JMH